In this Phase II STTR application Dr. Drost proposes to develop several miniaturized devices and techniques to measure blood flow and pressure in the mouse. These include: 1) miniaturizing the standard Transonic flow probes for use on vessels from 0.25 - 1.0 mm diameter; 2) development of ultrasound velocity indicator dilution methods for sensing cardiac output; 3) development apparatus and methods to measure organ blood flow and cardiac output from a single probe; 4) development of techniques and aids for surgery, sensor implantation, and chronic monitoring; 5) development of pressure sensor measurement protocols for vessels smaller than 1 mm; and 6) developing and publishing surgical methods and techniques for use in small animals. During Phase I they produced a workbook, showed some blood flow signals from the aortas of chronically instrumented mice, showed velocity dilution curves from rats, and showed pulsatile pressure signals from the carotid artery of a sheep. PROPOSED COMMERCIAL APPLICATION: NOT AVAILABLE